[Users] How to define max number of running VMs on a host?

[Itamar Heim]

On 08/22/2013 05:24 AM, lofyer wrote:
> On 2013/8/22 17:17, Itamar Heim wrote:
>> On 08/21/2013 01:19 AM, lof yer wrote:
>>> I didn't see anything like this in engine-config.
>>> Is it possible to do that without using host-hooks?
>>>
>>>
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>>
>> can you explain the use case a bit?
> I have 4 graphic workstations with 3 graphic cards on each. I wanna
> passthrough graphic cards to the VMs one by one, since one workstation
> has only 3 cards,  I must limit the number of running VM on a host to 3.

1. I assume you use a hook for the graphic passthrough?
you can just fail it if no more devices, and engine will try to schedule 
on next host.

2. (ab)use the reserved RAM. if you allocate to each VM reserved RAM so 
3 VMs can fit a host but 4 can't, engine won't try to schedule more than 
3 on the same host as it would violate the reserved rAM

3. not a hook, but a filter. in 3.3 you can write a new filter to the 
pluggable scheduler of "MaxNumberOfVms" and pass a property of 3 to it.